Tuning and go fast tips for a stock 440

[69 R/T]

I'm looking for new and updated tuning tips for today's gasoline and oils, etc. I have a 1969 Coronet R/T with a bone stock 440 still running the original single point distributor and Carter AVS 4617S carb (both professionally restored). The car starts and runs fine however I feel there's untapped potential lurking underneath that N96 air cleaner that wants to come out. Since this is a restored, numbers matching vehicle, I want to keep it as factory issued looking as possible and do not want to detract from stock appearing parts. And as much as I love that lumpy cam and header sound...I just cant do it to THIS car.

AVS jetting is Carter catalog stock, distributor has about 23 degrees built in, which allows me about 12 degrees of static timing to get 35-36 degrees total at WOT, vacuum advance has about another 12 degrees for cruising speeds. It's a 4 speed car with 3.54 gears by the way. It has a minor off idle stumble that I cant seem to correct by adjusting the acc. pump linkage and I'm sure the air valve secondary spring tension may need some tweaking. I figure the only other period correct stock go fast option is 4.10's I dont drive it much, but the jury is still out on those stiff gears...and the cost involved.

If anyone has a similar situation and has done some super tuning and would care to share their tips, I'd be grateful. And what's the latest in good motor oil these days? I've been out of the loop for a long time. Thanks guys!

 

[Tempest 455]

Some motors like more initial timing, you can limit the total if needed. If the carb has been rebuilt, the secondary spring may be loose or was never adjusted. Most off idle to WOT bog is caused by a lean spot. Can be accel pump, the sec spring tension or both. Overall jetting will also have an effect on how lean the motor goes at WOT, even when changes are made to the secondary side. You said lumpy cam and headers, so I'm guessing more duration/overlap cam than stock. You are going to need to jet the motor properly for that combination.

To start, use a vac gauge and set proper idle mixture and then you can move on to jetting. Every motor is different and you will have to see what your motor likes. I would start w/ timing, idle mixture and move up in jetting and see what happens.

 

[Cranky]

I'm in favor of more gear! Stock size tires? How is it for traction? Changing gear ratio is one of the best kick in the butt you have going for a stock setup.

 

[GTX MATT]

How quick does total timing come in? If its got the stock springs then swap them out, get total timing in by 2000-2500 RPM.

12 initial isn't bad, but does the engine want more?

Your total is in the right ball park.

Jet that Carter carb up, play with your metering rods and jets and step up springs. Look to the accelerator pump adjustment for your off idle bog first. What do the plugs look like?

 

[69 R/T]

Thanks Tempest, but I do not have a lumpy cam and headers. I mentioned that to deter people from telling me to do so. I did the vacuum gauge to get best idle and I have medium tension springs which brings in total timing a bit past 2000 rpm. I appreciate the advise!

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Hi Matt, Timing comes in just past 2000 rpm. My advance cam has 11.5 distributor degrees to make 23 crank degrees. I could play with it and squeeze a bit more until she "talks" to me then back it off a touch.

Believe it or not, I still have AFB and AVS Strip Kits from the 80's still floating around and a Carter catalog which lists every single carb and spec they made as a guide to go by. Plugs look about right. Not too white nor black, engine is low miles but an older rebuild.

The car is more for shows and light cruising but I still want the max I can get if possible because it's lots of fun to drive.

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Hi Cranky, I have BFG 245/60/15's on Magnum 500's which are about the same height as my repro stock F70-14 redlines on factory Road Wheels. As you know, there is no traction on bias ply skinnies, but the BFG's do ok for mild street use. I know that those 4.10's will snap me back, but I get hassled about too much revs and shortened engine life and possible regrets from my buddies. Hmmm...I still may just do it!

 

[GTX MATT]

There is an 8 degree plate out there for 16 crank degrees in the dizzy too, makes it easier than welding slots to give it a re-curve with a lot of initial. I've usually found them in '66 and earlier distributors. Sounds like your tune up is pretty solid already ignition wise though, I'd think she'd run pretty good. What are you running for points? That junk from Standard that is available now is NOT performance oriented. If thats whats in there find some good NOS Accel or Mallory heavy duty points. A buddy still has the points dizzy in his Road Runner and I found him some old Accel points at a swap meet. The car RPMs much nicer now.

Really the only other thing you can optimize without starting to change parts is in the carb. Maybe bring the car to a chassis dyno and get your air fuel really dialed in spot on. The old Carter stuff is nice to have! Plugs can be deceiving, especially with pump fuel. How does it look down INSIDE the plug? That's what you really want to see to find out about your WOT performance. Remember, the cars were lean when new, and stoic on E10 fuel is not 14.7 but closer to 14.1, so you're effectively even leaner compared to what they were new (if that makes sense). Don't forget to play with your secondary air door adjustment too.

You could block intake heat, but you'll have choke operation issues. Definitely tune tune tune first, but if you want to leave it stock appearing and really unleash some power you can get into head porting, intake porting, some blueprinting depending on what was done when it was built, and a Mr 6 Pack cam. A local guy just built a 440 with Bob's cam, the Eddy 6 pack setup, and bowl ported 906s with stock exhaust manifolds and made 427 hp and 496 ft lbs of torque. Nothing trick or deceiving about it.

Don't let your buddies talk you out of the 4.10s, if you don't want them thats fine but don't run taller gears because your buddies will hassle you. They just want you to be as slow as them!

 

[superbeedave]

My 2 cents worth. Raise the static timing to 15-16 degrees depending on duration at .05 on your cam may decide your static and go 8 percent richer on the jetting. That's a start.

 

[69 R/T]

Thanks a bunch guys. Y'all rock and it's much appreciated! My gal has me spend tons on her jewelry, now it's my turn!

 

[Meep-Meep]

You can actually do quite a bit with all factory parts including the intake but that will require a cam change. For starters the gas we have these days is not carb friendly so whatever you have to do to keep the carb cool is recommended for good drivability. If you don't get into the engine about all you can do is play with timing and jetting. Get an O2 sensor gizmo like the LM1 or LM2. The factory AVS can stand a tiny increase in the jetting but keep in mind you won't be able to get the original three step rods and jets so be prepared to convert it to the later Edelbrock stuff. Also have another look at your accelerator pump. It should give a nice strong shot even under light throttle application. And remember to readjust the plunger height when you make changes in the link position. If you want to get into the engine deeper and retain the factory look I have a pretty good recipe.

 

[69 R/T]

Meep-Meep, I'd really be interested in that famous recipe of yours. I'm curious! My buddy can't stand my car so stock. His famous quote is " Anyone can have a factory restored car, but it takes a real man to cut one up!" He'd love to put headers and bolt on's to my car when I'm not looking....lol